function foo() {
    var name = "why"
    var age = 18
  
    function bar() {
      debugger
      console.log(name)
    //   console.log(age)  //如果这里不用，V8引擎会自动帮我们销毁
    }
  
    return bar
  }
  
  var fn = foo()
  fn()
  
  